Last time i made this topic, people said it was impossible to get it to work. I dont believe that, because this DID work on my old router. When i changed routers and got back into running the server, i couldn't get it to work. :/

You'd have to connect through your external IP. Go to "www.whatismyip.com" or a similar website, get your external IP and server port, then type connect <server IP:port> in console. That way, you can connect externally.